This invention relates to the production of a double betaine salt corresponding to the formula EQU (CH.sub.3).sub.3 N.sup.+ --CH.sub.2 --COO.sup.-.Na.sup.+.Cl.sup.-.2H.sub.2 O (I)
which is useful as a seasoning agent.
Betaine is an internal salt corresponding to the formula EQU (CH.sub.3).sub.3 N.sup.+ --CH.sub.2 --COO.sup.-
in the form of colourless, deliquescent crystals. It crystallises from alcohol with 1 molecule of water which it loses at 100.degree. C. It is highly soluble in water, readily soluble in acetone and substantially insoluble in ether.
Betaine occurs widely in nature, especially in sugar beet. It can be synthesized, in particular from trimethylamine and chloroacetic acid, or by methylating aminoacetic acid (glycine). On an industrial scale, it is obtained for example from sugar beet molasses by way of its hydrochloride corresponding to the formula EQU (CH.sub.3).sub.3 N.sup.+ --CH.sub.2 --COO.sup.-.H.sup.+.Cl.sup.-
which readily dissolves in water, liberating free hydrochloric acid.
In the food industry, betaine hydrochloride is added to yeast powders as an acid component, and is also used in effervescent products as a substitute for organic acids such as tartaric acid, citric acid, etc.
Several attempts have been made to substitute salts of aminoacids for sodium chloride as seasoning agents. For example, U.S. Pat. No. 1,874,055 discloses the use of glutamates and U.S. Pat. No. 2,601,112 of mixtures of ammonium, potassium and choline salts having saline properties. Various betaine salts are disclosed, among which betaine sodium chloride sesquihydrate in Biochemistry J. 22, 1263 (1928) (no use of this salt being given) and betaine hydrochloride, aspartate and salicylate in Merck Index, 8th edition, 145 (1968) with the indication of their acidic or sweet and astringent taste. In published German patent application No. 2,300,492 a method of preparing betaine is disclosed, which comprises reacting betaine hydrochloride with sodium hydroxide and extracting betaine from the aqueous solution with an organic solvent.
The prior art, however, fails to indicate or even suggest that a new crystalline double betaine salt can be prepared in a very simple way which has interesting flavouring properties and is therefore suitable as a seasoning agent.